2 * ltt-ring-buffer-client.h
4 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * LTTng lib ring buffer client template.
8 * Dual LGPL v2.1/GPL v2 license.
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include "lib/bitfield.h"
14 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
15 #include "wrapper/trace-clock.h"
16 #include "ltt-events.h"
17 #include "ltt-tracer.h"
18 #include "wrapper/ringbuffer/frontend_types.h"
21 * Keep the natural field alignment for _each field_ within this structure if
22 * you ever add/remove a field from this header. Packed attribute is not used
23 * because gcc generates poor code on at least powerpc and mips. Don't ever
24 * let gcc add padding between the structure elements.
27 struct packet_header
{
28 /* Trace packet header */
31 * contains endianness information.
37 /* Stream packet context */
38 uint64_t timestamp_begin
; /* Cycle count at subbuffer start */
39 uint64_t timestamp_end
; /* Cycle count at subbuffer end */
40 uint32_t events_discarded
; /*
41 * Events lost in this subbuffer since
42 * the beginning of the trace.
45 uint32_t content_size
; /* Size of data in subbuffer */
46 uint32_t packet_size
; /* Subbuffer size (include padding) */
47 uint32_t cpu_id
; /* CPU id associated with stream */
48 uint8_t header_end
; /* End of header */
53 static inline notrace u64
lib_ring_buffer_clock_read(struct channel
*chan
)
55 return trace_clock_read64();
59 * record_header_size - Calculate the header size and padding necessary.
60 * @config: ring buffer instance configuration
62 * @offset: offset in the write buffer
63 * @pre_header_padding: padding to add before the header (output)
64 * @ctx: reservation context
66 * Returns the event header size (including padding).
68 * The payload must itself determine its own alignment from the biggest type it
72 unsigned char record_header_size(const struct lib_ring_buffer_config
*config
,
73 struct channel
*chan
, size_t offset
,
74 size_t *pre_header_padding
,
75 struct lib_ring_buffer_ctx
*ctx
)
77 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
78 size_t orig_offset
= offset
;
81 switch (ltt_chan
->header_type
) {
83 padding
= lib_ring_buffer_align(offset
, ltt_alignof(uint32_t));
85 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTT_RFLAG_EXTENDED
))) {
86 offset
+= sizeof(uint32_t); /* id and timestamp */
88 /* Minimum space taken by 5-bit id */
89 offset
+= sizeof(uint8_t);
90 /* Align extended struct on largest member */
91 offset
+= lib_ring_buffer_align(offset
, ltt_alignof(uint64_t));
92 offset
+= sizeof(uint32_t); /* id */
93 offset
+= lib_ring_buffer_align(offset
, ltt_alignof(uint64_t));
94 offset
+= sizeof(uint64_t); /* timestamp */
98 padding
= lib_ring_buffer_align(offset
, ltt_alignof(uint16_t));
100 offset
+= sizeof(uint16_t);
101 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTT_RFLAG_EXTENDED
))) {
102 offset
+= lib_ring_buffer_align(offset
, ltt_alignof(uint32_t));
103 offset
+= sizeof(uint32_t); /* timestamp */
105 /* Align extended struct on largest member */
106 offset
+= lib_ring_buffer_align(offset
, ltt_alignof(uint64_t));
107 offset
+= sizeof(uint32_t); /* id */
108 offset
+= lib_ring_buffer_align(offset
, ltt_alignof(uint64_t));
109 offset
+= sizeof(uint64_t); /* timestamp */
117 *pre_header_padding
= padding
;
118 return offset
- orig_offset
;
121 #include "wrapper/ringbuffer/api.h"
124 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
125 struct lib_ring_buffer_ctx
*ctx
,
129 * ltt_write_event_header
131 * Writes the event header to the offset (already aligned on 32-bits).
133 * @config: ring buffer instance configuration
134 * @ctx: reservation context
135 * @event_id: event ID
138 void ltt_write_event_header(const struct lib_ring_buffer_config
*config
,
139 struct lib_ring_buffer_ctx
*ctx
,
142 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
144 if (unlikely(ctx
->rflags
))
147 switch (ltt_chan
->header_type
) {
148 case 1: /* compact */
150 uint32_t id_time
= 0;
152 bt_bitfield_write(&id_time
, uint32_t, 0, 5, event_id
);
153 bt_bitfield_write(&id_time
, uint32_t, 5, 27, ctx
->tsc
);
154 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
159 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
161 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
162 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint32_t));
163 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
172 ltt_write_event_header_slow(config
, ctx
, event_id
);
175 void ltt_write_event_header_slow(const struct lib_ring_buffer_config
*config
,
176 struct lib_ring_buffer_ctx
*ctx
,
179 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
181 switch (ltt_chan
->header_type
) {
182 case 1: /* compact */
183 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTT_RFLAG_EXTENDED
))) {
184 uint32_t id_time
= 0;
186 bt_bitfield_write(&id_time
, uint32_t, 0, 5, event_id
);
187 bt_bitfield_write(&id_time
, uint32_t, 5, 27, ctx
->tsc
);
188 lib_ring_buffer_write(config
, ctx
, &id_time
, sizeof(id_time
));
191 uint64_t timestamp
= ctx
->tsc
;
193 bt_bitfield_write(&id
, uint8_t, 0, 5, 31);
194 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
195 /* Align extended struct on largest member */
196 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
197 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
198 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
199 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
204 if (!(ctx
->rflags
& (RING_BUFFER_RFLAG_FULL_TSC
| LTT_RFLAG_EXTENDED
))) {
205 uint32_t timestamp
= (uint32_t) ctx
->tsc
;
207 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
208 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint32_t));
209 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
212 uint64_t timestamp
= ctx
->tsc
;
214 lib_ring_buffer_write(config
, ctx
, &id
, sizeof(id
));
215 /* Align extended struct on largest member */
216 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
217 lib_ring_buffer_write(config
, ctx
, &event_id
, sizeof(event_id
));
218 lib_ring_buffer_align_ctx(ctx
, ltt_alignof(uint64_t));
219 lib_ring_buffer_write(config
, ctx
, ×tamp
, sizeof(timestamp
));
228 static const struct lib_ring_buffer_config client_config
;
230 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
232 return lib_ring_buffer_clock_read(chan
);
236 size_t client_record_header_size(const struct lib_ring_buffer_config
*config
,
237 struct channel
*chan
, size_t offset
,
238 size_t *pre_header_padding
,
239 struct lib_ring_buffer_ctx
*ctx
)
241 return record_header_size(config
, chan
, offset
,
242 pre_header_padding
, ctx
);
246 * client_packet_header_size - called on buffer-switch to a new sub-buffer
248 * Return header size without padding after the structure. Don't use packed
249 * structure because gcc generates inefficient code on some architectures
252 static size_t client_packet_header_size(void)
254 return offsetof(struct packet_header
, ctx
.header_end
);
257 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
258 unsigned int subbuf_idx
)
260 struct channel
*chan
= buf
->backend
.chan
;
261 struct packet_header
*header
=
262 (struct packet_header
*)
263 lib_ring_buffer_offset_address(&buf
->backend
,
264 subbuf_idx
* chan
->backend
.subbuf_size
);
265 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
266 struct ltt_session
*session
= ltt_chan
->session
;
268 header
->magic
= CTF_MAGIC_NUMBER
;
269 memcpy(header
->uuid
, session
->uuid
.b
, sizeof(session
->uuid
));
270 header
->stream_id
= ltt_chan
->id
;
271 header
->ctx
.timestamp_begin
= tsc
;
272 header
->ctx
.timestamp_end
= 0;
273 header
->ctx
.events_discarded
= 0;
274 header
->ctx
.content_size
= 0xFFFFFFFF; /* for debugging */
275 header
->ctx
.packet_size
= 0xFFFFFFFF;
276 header
->ctx
.cpu_id
= buf
->backend
.cpu
;
280 * offset is assumed to never be 0 here : never deliver a completely empty
281 * subbuffer. data_size is between 1 and subbuf_size.
283 static void client_buffer_end(struct lib_ring_buffer
*buf
, u64 tsc
,
284 unsigned int subbuf_idx
, unsigned long data_size
)
286 struct channel
*chan
= buf
->backend
.chan
;
287 struct packet_header
*header
=
288 (struct packet_header
*)
289 lib_ring_buffer_offset_address(&buf
->backend
,
290 subbuf_idx
* chan
->backend
.subbuf_size
);
291 unsigned long records_lost
= 0;
293 header
->ctx
.timestamp_end
= tsc
;
294 header
->ctx
.content_size
= data_size
* CHAR_BIT
; /* in bits */
295 header
->ctx
.packet_size
= PAGE_ALIGN(data_size
) * CHAR_BIT
; /* in bits */
296 records_lost
+= lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
297 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
298 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
299 header
->ctx
.events_discarded
= records_lost
;
302 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
303 int cpu
, const char *name
)
308 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
)
312 static const struct lib_ring_buffer_config client_config
= {
313 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
314 .cb
.record_header_size
= client_record_header_size
,
315 .cb
.subbuffer_header_size
= client_packet_header_size
,
316 .cb
.buffer_begin
= client_buffer_begin
,
317 .cb
.buffer_end
= client_buffer_end
,
318 .cb
.buffer_create
= client_buffer_create
,
319 .cb
.buffer_finalize
= client_buffer_finalize
,
322 .alloc
= RING_BUFFER_ALLOC_PER_CPU
,
323 .sync
= RING_BUFFER_SYNC_PER_CPU
,
324 .mode
= RING_BUFFER_MODE_TEMPLATE
,
325 .backend
= RING_BUFFER_PAGE
,
326 .output
= RING_BUFFER_SPLICE
,
327 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
328 .ipi
= RING_BUFFER_IPI_BARRIER
,
329 .wakeup
= RING_BUFFER_WAKEUP_BY_TIMER
,
333 struct channel
*_channel_create(const char *name
,
334 struct ltt_channel
*ltt_chan
, void *buf_addr
,
335 size_t subbuf_size
, size_t num_subbuf
,
336 unsigned int switch_timer_interval
,
337 unsigned int read_timer_interval
)
339 return channel_create(&client_config
, name
, ltt_chan
, buf_addr
,
340 subbuf_size
, num_subbuf
, switch_timer_interval
,
341 read_timer_interval
);
345 void ltt_channel_destroy(struct channel
*chan
)
347 channel_destroy(chan
);
351 struct lib_ring_buffer
*ltt_buffer_read_open(struct channel
*chan
)
353 struct lib_ring_buffer
*buf
;
356 for_each_channel_cpu(cpu
, chan
) {
357 buf
= channel_get_ring_buffer(&client_config
, chan
, cpu
);
358 if (!lib_ring_buffer_open_read(buf
))
365 void ltt_buffer_read_close(struct lib_ring_buffer
*buf
)
367 lib_ring_buffer_release_read(buf
);
372 int ltt_event_reserve(struct lib_ring_buffer_ctx
*ctx
,
375 struct ltt_channel
*ltt_chan
= channel_get_private(ctx
->chan
);
378 cpu
= lib_ring_buffer_get_cpu(&client_config
);
383 switch (ltt_chan
->header_type
) {
384 case 1: /* compact */
386 ctx
->rflags
|= LTT_RFLAG_EXTENDED
;
389 if (event_id
> 65534)
390 ctx
->rflags
|= LTT_RFLAG_EXTENDED
;
396 ret
= lib_ring_buffer_reserve(&client_config
, ctx
);
399 ltt_write_event_header(&client_config
, ctx
, event_id
);
402 lib_ring_buffer_put_cpu(&client_config
);
407 void ltt_event_commit(struct lib_ring_buffer_ctx
*ctx
)
409 lib_ring_buffer_commit(&client_config
, ctx
);
410 lib_ring_buffer_put_cpu(&client_config
);
414 void ltt_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
417 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
421 wait_queue_head_t
*ltt_get_reader_wait_queue(struct ltt_channel
*chan
)
423 return &chan
->chan
->read_wait
;
426 static struct ltt_transport ltt_relay_transport
= {
427 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
,
428 .owner
= THIS_MODULE
,
430 .channel_create
= _channel_create
,
431 .channel_destroy
= ltt_channel_destroy
,
432 .buffer_read_open
= ltt_buffer_read_open
,
433 .buffer_read_close
= ltt_buffer_read_close
,
434 .event_reserve
= ltt_event_reserve
,
435 .event_commit
= ltt_event_commit
,
436 .event_write
= ltt_event_write
,
437 .packet_avail_size
= NULL
, /* Would be racy anyway */
438 .get_reader_wait_queue
= ltt_get_reader_wait_queue
,
442 static int __init
ltt_ring_buffer_client_init(void)
445 * This vmalloc sync all also takes care of the lib ring buffer
446 * vmalloc'd module pages when it is built as a module into LTTng.
448 wrapper_vmalloc_sync_all();
449 printk(KERN_INFO
"LTT : ltt ring buffer client init\n");
450 ltt_transport_register(<t_relay_transport
);
454 module_init(ltt_ring_buffer_client_init
);
456 static void __exit
ltt_ring_buffer_client_exit(void)
458 printk(KERN_INFO
"LTT : ltt ring buffer client exit\n");
459 ltt_transport_unregister(<t_relay_transport
);
462 module_exit(ltt_ring_buffer_client_exit
);
464 MODULE_LICENSE("GPL and additional rights");
465 MODULE_AUTHOR("Mathieu Desnoyers");
466 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING